Method of operating an air pump for a boosted gas burner assembly

ABSTRACT

A gas burner assembly and a method of operating the same are provided. The gas burner assembly includes fuel regulating device for providing a flow of fuel and an air pump for providing a flow of air to a boost burner for combustion. The method includes stopping the flow of fuel using the fuel regulating device and ramping down the operation of the air pump to slowly stop the flow of air. For example, the flow rate of the flow of air may decrease linearly over a predetermined time period to ensure a lean fuel/air mixture is not provided to the boost burner which may result in undesirable flame characteristics.

FIELD OF THE INVENTION

The present subject matter relates generally to gas burners, and moreparticularly to forced air gas burners for providing fuel/air ratios forimproved combustion.

BACKGROUND OF THE INVENTION

Conventional gas cooking appliances have one or more gas burners, e.g.,positioned at a cooktop surface for use in heating or cooking an object,such as a cooking utensil and its contents. These gas burners typicallycombust a mixture of gaseous fuel and air to generate heat for cooking.Known burners frequently include an orifice, a Venturi mixing throat,and a plurality of flame ports. The orifice ejects a jet of gaseous fuelwhich entrains air while passing through the Venturi mixing throat. Theair and gaseous fuel mix within the Venturi mixing throat before themixture is combusted at the flame ports of the burners. Such burners aregenerally referred to as naturally aspirated gas burners.

Naturally aspirated gas burners can efficiently burn gaseous fuel.However, a power output of naturally aspirated gas burners is limited bythe ability to entrain a suitable volume of air into the Venturi mixingthroat with the jet of gaseous fuel. Moreover, there is a trend in thecooking appliance market toward high-powered burners in order to speedup cooking tasks. Thus, to provide increased entrainment of air, certaingas burners include a fan or air pump that supplies pressurized air formixing with the jet of gaseous fuel. Such gas burners are generallyreferred to as forced air gas burners.

While offering increased power, known forced air gas burners suffer fromvarious drawbacks. For example, while well designed gas burnersdemonstrate stable flame characteristics over a wide range of operatingconditions, these burners may suffer from some undesirable transienttraits. One such trait is known as “extinction pop,” which is a smallexplosion that takes place inside the burner head when it is shut off,resulting in a loud and undesirable popping sound. Extinction popresults from the last bit of fuel entering the burner after fuel shutoff mixing with excessive air and creating a fuel lean condition for abrief period. This is because at steady state the air is flowing intothe mixing throat with momentum and this inductance continues to pullair in for slight moment while the fuel has been abruptly halted. Thus,the last remaining fuel entering the burner is mixed with too much air,creating an excessively lean mixture that burns faster than it exits theburner ports such that the flame front passes into the burner head whereremaining fuel/air mix burns rapidly and creates the pop. Boosted burnerdesigns, due to their high relative amount of total port cross sectionalarea and large venturis, are more prone to extinction pop.

Accordingly, a cooktop appliance including a boosted burner withimproved transient operating characteristics would be desirable. Morespecifically, a gas burner assembly that could avoid or mitigate theinherent tendencies to pop after the boost burner is shut off or hasexpired would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be apparent from the description, or maybe learned through practice of the invention.

In a first example embodiment, a method of operating a gas burnerassembly is provided. The gas burner assembly includes a boost burner, afuel regulating device for providing a flow of fuel to the boost burner,and an air pump for providing a flow of air to the boost burner. Themethod includes stopping the flow of fuel using the fuel regulatingdevice and ramping down the operation of the air pump to slowly stop theflow of air.

In a second example embodiment, a method of operating a gas burnerassembly is provided. The gas burner assembly includes a boost burner, afuel regulating device for providing a flow of fuel to the boost burner,an air pump for providing a flow of air to the boost burner, and apneumatically controlled valve for stopping the flow of fuel when apressure of the flow of air drops below a predetermined thresholdpressure. The method includes ramping down the operation of the air pumpto slowly stop the flow of air until a pressure of the flow of air dropsbelow the predetermined threshold to close the pneumatically controlledvalve and stop the flow of fuel and continuing to ramp down theoperation of the air pump until the flow of air stops.

According to still another embodiment, a gas burner assembly for acooktop appliance is provided. The gas burner assembly includes a boostburner including a plurality of boost flame ports in fluid communicationwith a boost fuel chamber, a fuel regulating device fluidly coupled tothe boost fuel chamber for providing a flow of fuel to the boost fuelchamber, and an air pump for selectively urging a flow of air into theboost fuel chamber. A controller is operably coupled to the fuelregulating device and the air pump for stopping the flow of fuel usingthe fuel regulating device and ramping down the operation of the airpump to slowly stop the flow of air.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures.

FIG. 1 provides a top, plan view of a cooktop appliance according to anexample embodiment of the present disclosure.

FIG. 2 is a side elevation view of a gas burner assembly that may beused with the exemplary cooktop appliance of FIG. 1 according to anexemplary embodiment of the present subject matter.

FIG. 3 is an exploded view of the example gas burner of assembly FIG. 2.

FIG. 4 is a section view of the example gas burner assembly of FIG. 2.

FIG. 5 is another section view of the example gas burner assembly ofFIG. 2.

FIG. 6 is a perspective view of an injet of the example gas burnerassembly of FIG. 2.

FIG. 7 is an exploded view of the injet of FIG. 7.

FIG. 8 is a section view of the injet of FIG. 7.

FIG. 9 depicts certain components of a controller according to exampleembodiments of the present subject matter.

FIG. 10 is a schematic view of a gas burner assembly and a fuel supplysystem according to an example embodiment of the present subject matter.

FIG. 11 is a method of operating a gas burner assembly in accordancewith one embodiment of the present disclosure.

FIG. 12 provides a plot illustrating the operating voltage of an airpump for a boosted burner during steady state and shut down according toan exemplary embodiment of the present subject matter.

FIG. 13 is a method of operating a gas burner assembly in accordancewith one embodiment of the present disclosure.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

The present disclosure relates generally to a gas burner for a cooktopappliance 100. Although cooktop appliance 100 is used below for thepurpose of explaining the details of the present subject matter, it willbe appreciated that the present subject matter may be used in or withany other suitable appliance in alternative example embodiments. Forexample, the gas burner described below may be used on other types ofcooking appliances, such as single or double oven range appliances.Cooktop appliance 100 is used in the discussion below only for thepurpose of explanation, and such use is not intended to limit the scopeof the present disclosure to any particular style of appliance.

FIG. 1 illustrates an exemplary embodiment of a cooktop appliance 100 ofthe present disclosure. Cooktop appliance 100 may be, e.g., fittedintegrally with a surface of a kitchen counter, may be configured as aslide-in cooktop unit, or may be a part of a free-standing range cookingappliance. Cooktop appliance 100 includes a top panel 102 that includesone or more heating sources, such as heating elements 104 for use in,e.g., heating or cooking. Top panel 102, as used herein, refers to anyupper surface of cooktop appliance 100 on which utensils may be heatedand therefore food cooked. In general, top panel 102 may be constructedof any suitably rigid and heat resistant material capable of supportingheating elements 104, cooking utensils, and/or other components ofcooktop appliance 100. By way of example, top panel 102 may beconstructed of enameled steel, stainless steel, glass, ceramics, andcombinations thereof.

According to the illustrated embodiment, cooktop appliance 100 isgenerally referred to as a “gas cooktop,” and heating elements 104 aregas burners. For example, one or more of the gas burners in cooktopappliance 100 may be a gas burner 120 described below. As illustrated,heating elements 104 are positioned on and/or within top panel 102 andhave various sizes, as shown in FIG. 1, so as to provide for the receiptof cooking utensils (i.e., pots, pans, etc.) of various sizes andconfigurations and to provide different heat inputs for such cookingutensils.

In addition, cooktop appliance 100 may include one or more grates 106configured to support a cooking utensil, such as a pot, pan, etc. Ingeneral, grates 106 include a plurality of elongated members 108, e.g.,formed of cast metal, such as cast iron. The cooking utensil may beplaced on the elongated members 108 of each grate 106 such that thecooking utensil rests on an upper surface of elongated members 108during the cooking process. Heating elements 104 are positionedunderneath the various grates 106 such that heating elements 104 providethermal energy to cooking utensils above top panel 102 by combustion offuel below the cooking utensils.

According to the illustrated example embodiment, a user interface panelor control panel 110 is located within convenient reach of a user ofcooktop appliance 100. For this example embodiment, control panel 110includes control knobs 112 that are each associated with one of heatingelements 104. Control knobs 112 allow the user to activate each heatingelement 104 and regulate the amount of heat input each heating element104 provides to a cooking utensil located thereon, as described in moredetail below. Although cooktop appliance 100 is illustrated as includingcontrol knobs 112 for controlling heating elements 104, it will beunderstood that control knobs 112 and the configuration of cooktopappliance 100 shown in FIG. 1 is provided by way of example only. Morespecifically, control panel 110 may include various input components,such as one or more of a variety of touch-type controls, electrical,mechanical or electro-mechanical input devices including rotary dials,push buttons, and touch pads.

According to the illustrated embodiment, control knobs 112 are locatedwithin control panel 110 of cooktop appliance 100. However, it should beappreciated that this location is used only for the purpose ofexplanation, and that other locations and configurations of controlpanel 110 and control knobs 112 are possible and within the scope of thepresent subject matter. Indeed, according to alternative embodiments,control knobs 112 may instead be located directly on top panel 102 orelsewhere on cooktop appliance 100, e.g., on a backsplash, front bezel,or any other suitable surface of cooktop appliance 100. Control panel110 may also be provided with one or more graphical display devices,such as a digital or analog display device designed to provideoperational feedback to a user.

Turning now to FIGS. 2 through 8, a gas burner 120 according to anexample embodiment of the present disclosure is described. Gas burner120 may be used in cooktop appliance 100, e.g., as one of heatingelements 104. Thus, gas burner 120 is described in greater detail belowin the context of cooktop appliance 100. However, it will be understoodthat gas burner 120 may be used in or with any other suitable cooktopappliance in alternative example embodiments.

Gas burner 120 includes a burner body 122. Burner body 122 generallydefines a first burner ring or stage (e.g., a primary burner 130) and asecond burner ring or stage (e.g., a boost burner 132). Morespecifically, primary burner 130 generally includes a plurality ofnaturally aspirated or primary flame ports 134 and a primary fuelchamber 136 which are defined at least in part by burner body 122.Similarly, boost burner 132 generally includes a plurality of forced airor boost flame ports 138 and a boost fuel chamber 140 which are definedat least in part by burner body 122.

As illustrated, primary flame ports 134 and boost flame ports 138 mayboth be distributed in rings on burner body 122. In addition, primaryflame ports 134 may be positioned concentric with boost flame ports 138.Further, primary flame ports 134 (and primary burner 130) may bepositioned below boost flame ports 138 (and boost burner 132). Suchpositioning of primary burner 130 relative to boost burner 132 mayimprove combustion of gaseous fuel when gas burner assembly 120 is setto the boost position. For example, flames at primary burner 130 mayassist with lighting gaseous fuel at boost burner 132 due to theposition of primary burner 130 below boost burner 132.

With reference to FIGS. 2 through 8, gas burner 120 also includes aninjet assembly 150. Injet assembly 150 may be positioned below top panel102, e.g., below an opening 103 (FIG. 3) of top panel 102. Conversely,burner body 122 may be positioned on top panel 102, e.g., over opening103 of top panel 102. Thus, burner body 122 may cover opening 103 of toppanel 102 when burner body 122 is positioned on top panel 102. Whenburner body 122 is removed from top panel 102, injet assembly 150 belowtop panel 102 is accessible through opening 103. Thus, e.g., a fuelorifice(s) of gas burner 120 on injet assembly 150 may be accessed byremoving burner body 122 from top panel 102, and an installer may reachthrough opening 103 (e.g., with a wrench or other suitable tool) tochange out the fuel orifice(s) of gas burner 120.

Injet assembly 150 is configured for directing a flow of gaseous fuel toprimary flame ports 134 of burner body 122. Thus, injet assembly 150 maybe coupled to a gaseous fuel source 152, as described in more detailbelow with reference to FIG. 10. During operation of gas burner 120,gaseous fuel from gaseous fuel source 152 may flow from injet assembly150 into a vertical Venturi mixing tube 154. In particular, injetassembly 150 includes a first gas orifice 156 that is in fluidcommunication with a gas passage 158. A jet of gaseous fuel from gaseousfuel source 152 may exit injet assembly 150 at first gas orifice 156 andflow towards vertical Venturi mixing tube 154. Between first gas orifice156 and vertical Venturi mixing tube 154, the jet of gaseous fuel fromfirst gas orifice 156 may entrain air into vertical Venturi mixing tube154. Air and gaseous fuel may mix within vertical Venturi mixing tube154 prior to flowing into primary fuel chamber 136 and through primaryflame ports 134 where the mixture of air and gaseous fuel may becombusted.

Injet assembly 150 is also configured for directing a flow of air andgaseous fuel to boost flame ports 138 of burner body 122. Thus, asdiscussed in greater detail below, injet assembly 150 may be coupled topressurized air source 160 in addition to gaseous fuel source 152.During boosted operation of gas burner 120, a mixed flow of gaseous fuelfrom gaseous fuel source 152 and air from pressurized air source 160 mayflow from injet assembly 150, through an inlet tube 162, and into boostfuel chamber 140 prior to flowing to boost flame ports 138 where themixture of gaseous fuel and air may be combusted at boost flame ports138.

In addition to first gas orifice 156, injet assembly 150 also includes asecond gas orifice 164, a mixed outlet nozzle 166, and an injet body168. Injet body 168 defines an air passage 170 and gas passage 158. Airpassage 170 may be in fluid communication with pressurized air source160. For example, a pipe or conduit may extend between pressurized airsource 160 and injet body 168, and pressurized air from pressurized airsource 160 may flow into air passage 170 via such pipe or conduit. Gaspassage 158 may be in fluid communication with gaseous fuel source 152.For example, a pipe or conduit may extend between gaseous fuel source152 and injet body 168, and gaseous fuel from gaseous fuel source 152may flow into gas passage 158 via such pipe or conduit. In certainexample embodiments, injet body 168 defines a single inlet 172 for airpassage 170 through which the pressurized air from pressurized airsource 160 may flow into air passage 170, and injet body 168 defines asingle inlet 174 for gas passage 158 through which the pressurized airfrom gaseous fuel source 152 may flow into gas passage 158.

First gas outlet orifice 156 is mounted to injet body 168, e.g., at afirst outlet of gas passage 158. Thus, gaseous fuel from gaseous fuelsource 152 may exit gas passage 158 through first gas outlet orifice156, and gas passage 158 is configured for directing a flow of gaseousfuel through injet body 168 to first gas outlet orifice 156. On injetbody 168, first gas outlet orifice 156 is oriented for directing a flowof gaseous fuel towards vertical Venturi mixing tube 154 and/or primaryflame ports 134, as discussed above.

Second gas orifice 164 and injet body 168, e.g., collectively, form aneductor mixer 176 within a mixing chamber 178 of injet body 168. Eductormixer 176 is configured for mixing pressurized air from air passage 170with gaseous fuel from gas passage 158 in mixing chamber 178. Inparticular, an outlet 180 of air passage 170 is positioned at mixingchamber 178. A jet of pressurized air from pressurized air source 160may flow from air passage 170 into mixing chamber 178 via outlet 180 ofair passage 170. Second gas orifice 164 is positioned within injet body168 between mixing chamber 178 and gas passage 158. Gaseous fuel fromgaseous fuel source 152 may flow from gas passage 158 into mixingchamber 178 via second gas orifice 164. As an example, second gasorifice 164 may be a plate that defines a plurality of through holes182, and the gaseous fuel in gas passage 158 may flow through holes 182into mixing chamber 178.

The jet of pressurized air flowing into mixing chamber 178 via outlet180 of air passage 170 may draw and entrain gaseous fuel flowing intomixing chamber 178 via second gas orifice 164. In addition, as thegaseous fuel is entrained into the air, a mixture of air and gaseousfuel is formed within mixing chamber 178. From mixing chamber 178, themixture of air and gaseous fuel may flow from mixing chamber 178 viamixed outlet nozzle 166. In particular, mixed outlet nozzle 166 ismounted to injet body 168 at mixing chamber 178, and mixed outlet nozzle166 is oriented on injet body 168 for directing the mixed flow of airand gaseous fuel from mixing chamber 178, through inlet tube 162, intoboost fuel chamber 140, and/or towards boost flame ports 138, asdiscussed above.

Burner body 122 may be positioned over injet body 168, e.g., when burnerbody 122 is positioned on top panel 102. In addition, first gas orifice156 may be oriented on injet body 168 such that first gas orifice 156directs the flow of gaseous fuel upwardly towards vertical Venturimixing tube 154 and primary flame ports 134. Similarly, mixed outletnozzle 166 may be oriented on injet body 168 such that mixed outletnozzle 166 directs the mixed flow of air and gaseous fuel upwardlytowards inlet tube 162 and boost flame ports 138.

First and second gas orifices 156, 164 may be removeable from injet body168. First and second gas orifices 156, 164 may also be positioned oninjet body 168 directly below burner body 122, e.g., when burner body122 is positioned on top panel 102. Thus, e.g., first and second gasorifices 156, 164 may be accessed by removing burner body 122 from toppanel 102, and an installer may reach through opening 103 (e.g., with awrench or other suitable tool) to change out first and second gasorifices 156, 164.

Injet assembly 150 also includes a pneumatically actuated gas valve 200.Pneumatically actuated gas valve 200 may be positioned within injet body168, and pneumatically actuated gas valve 200 is adjustable between aclosed configuration and an open configuration. In the closedconfiguration, pneumatically actuated gas valve 200 blocks the flow ofgaseous fuel through gas passage 158 to second gas orifice 164, eductormixer 176, and/or mixed outlet nozzle 166. Conversely, pneumaticallyactuated gas valve 200 permits the flow of gaseous fuel through gaspassage 158 to second gas orifice 164/eductor mixer 176 in the openconfiguration. Pneumatically actuated gas valve 200 is configured toadjust from the closed configuration to the open configuration inresponse to the flow of air through air passage 170 to outlet 180 of airpassage 170. Thus, e.g., pneumatically actuated gas valve 200 is influid communication with air passage 170 and opens in response to airpassage 170 being pressurized by air from pressurized air source 160. Asan example, pneumatically actuated gas valve 200 may be positioned on abranch of air passage 170 relative to outlet 180 of air passage 170.

It will be understood that first gas outlet orifice 156 may be in fluidcommunication with gas passage 158 in both the open and closedconfigurations of pneumatically actuated gas valve 200. Thus, first gasoutlet orifice 156 may be positioned on gas passage 158 upstream ofpneumatically actuated gas valve 200 relative to the flow of gas throughgas passage 158. Thus, e.g., pneumatically actuated gas valve 200 maynot regulate the flow of gas through second gas orifice 164 but notfirst gas outlet orifice 156.

As shown in FIGS. 5 and 7, pneumatically actuated gas valve 200 includesa diaphragm 202, a seal 204, and a plug 206. Diaphragm 202 is positionedbetween air passage 170 and gas passage 158 within injet body 168. Forexample, diaphragm 202 may be circular and may be clamped between afirst injet body half 208 and a second injet body half 210. Inparticular, first and second injet body halves 208, 210 may be fastenedtogether with diaphragm 202 positioned between first and second injetbody halves 208, 210.

Seal 204 is mounted to injet body 168 within gas passage 158. Plug 206is mounted to diaphragm 202, e.g., such that plug 206 travels withdiaphragm 202 when diaphragm 202 deforms. Plug 206 is positioned againstseal 204 when pneumatically actuated gas valve 200 is closed. A spring212 may be coupled to plug 206. Spring 212 may urge plug 206 towardsseal 204. Thus, pneumatically actuated gas valve 200 may be normallyclosed.

When air passage 170 is pressurized by air from pressurized air source160, diaphragm 202 may deform due to the pressure of air in air passage170 increasing, and plug 206 may shift away from seal 204 as diaphragm202 deforms. In such a manner, diaphragm 202, seal 204, and plug 206 maycooperate to open pneumatically actuated gas valve 200 in response toair passage 170 being pressurized by air from pressurized air source160. Conversely, diaphragm 202 may return to an undeformed state whenair passage 170 is no longer pressurized by air from pressurized airsource 160, and plug 206 may shift against seal 204. In such a manner,diaphragm 202, seal 204 and plug 206 may cooperate to closepneumatically actuated gas valve 200 in response to air passage 170 nolonger being pressurized by air from pressurized air source 160.

Operation of cooktop appliance 100 and gas burner assemblies 120 may becontrolled by electromechanical switches or by a controller orprocessing device 220 (FIGS. 1 and 9) that is operatively coupled tocontrol panel 110 for user manipulation, e.g., to control the operationof heating elements 104. In response to user manipulation of controlpanel 110 (e.g., via control knobs 112 and/or a touch screen interface),controller 220 operates the various components of cooktop appliance 100to execute selected instructions, commands, or other features.

As described in more detail below with respect to FIG. 9, controller 220may include a memory and microprocessor, such as a general or specialpurpose microprocessor operable to execute programming instructions ormicro-control code associated with appliance operation. Alternatively,controller 220 may be constructed without using a microprocessor, e.g.,using a combination of discrete analog and/or digital logic circuitry(such as switches, amplifiers, integrators, comparators, flip-flops, ANDgates, and the like) to perform control functionality instead of relyingupon software. Control panel 110 and other components of cooktopappliance 100 may be in communication with controller 220 via one ormore signal lines or shared communication busses.

FIG. 9 depicts certain components of controller 220 according to exampleembodiments of the present disclosure. Controller 220 can include one ormore computing device(s) 220A which may be used to implement methods asdescribed herein. Computing device(s) 220A can include one or moreprocessor(s) 220B and one or more memory device(s) 220C. The one or moreprocessor(s) 220B can include any suitable processing device, such as amicroprocessor, microcontroller, integrated circuit, an applicationspecific integrated circuit (ASIC), a digital signal processor (DSP), afield-programmable gate array (FPGA), logic device, one or more centralprocessing units (CPUs), graphics processing units (GPUs) (e.g.,dedicated to efficiently rendering images), processing units performingother specialized calculations, etc. The memory device(s) 220C caninclude one or more non-transitory computer-readable storage medium(s),such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks,etc., and/or combinations thereof.

The memory device(s) 220C can include one or more computer-readablemedia and can store information accessible by the one or moreprocessor(s) 220B, including instructions 220D that can be executed bythe one or more processor(s) 220B. For instance, the memory device(s)220C can store instructions 220D for running one or more softwareapplications, displaying a user interface, receiving user input,processing user input, etc. In some implementations, the instructions220D can be executed by the one or more processor(s) 220B to cause theone or more processor(s) 220B to perform operations, e.g., such as oneor more portions of methods described herein. The instructions 220D canbe software written in any suitable programming language or can beimplemented in hardware. Additionally, and/or alternatively, theinstructions 220D can be executed in logically and/or virtually separatethreads on processor(s) 220B.

The one or more memory device(s) 220C can also store data 220E that canbe retrieved, manipulated, created, or stored by the one or moreprocessor(s) 220B. The data 220E can include, for instance, data tofacilitate performance of methods described herein. The data 220E can bestored in one or more database(s). The one or more database(s) can beconnected to controller 220 by a high bandwidth LAN or WAN, or can alsobe connected to controller through one or more networks (not shown). Theone or more database(s) can be split up so that they are located inmultiple locales. In some implementations, the data 220E can be receivedfrom another device.

The computing device(s) 220A can also include a communication module orinterface 220F used to communicate with one or more other component(s)of controller 220 or cooktop appliance 100 over the network. Thecommunication interface 220F can include any suitable components forinterfacing with one or more network(s), including for example,transmitters, receivers, ports, controllers, antennas, or other suitablecomponents.

Referring now to FIG. 10, a schematic view of gas burner assembly 120and a fuel supply system 230 will be described. In general, fuel supplysystem 230 is configured for selectively supplying gaseous fuel such aspropane or natural gas to primary burner 130 and boost burner 132 toregulate the amount of heat generated by the respective stages. Inparticular, fuel supply system 230 is configured for selectivelysupplying gaseous fuel to only primary burner 130 or to both primaryburner 130 and boost burner 132 depending upon the desired output of gasburner assembly 120 selected by a user of gas burner assembly 120. Thus,primary burner 130 is separate or independent from boost burner 132,e.g., such that primary burner 130 is not in fluid communication withboost burner 132 within gas burner assembly 120. In such manner, gaseousfuel within gas burner assembly 120 does not flow between primary burner130 and boost burner 132.

As shown in FIG. 10, fuel supply system 230 includes a supply line 232that may be coupled to pressurized gaseous fuel source 152, such as anatural gas supply line or a propane tank. In this manner, a flow ofsupply fuel (indicated by arrow 234), such as gaseous fuel (e.g.,natural gas or propane), is flowable from the pressurized gaseous fuelsource 152 into supply line 232. Fuel supply system 230 further includesa fuel regulating device 236 operably coupled to supply line 232 forselectively directing a metered amount of fuel to primary burner 130 andboost burner 132.

More specifically, according to an exemplary embodiment, control knob112 may be operably coupled to fuel regulating device 236 for regulatingthe flow of supply fuel 234. In this regard, a user may rotate controlknob 112 to adjust the position of fuel regulating device 236 and theflow of supply fuel 234 through supply line 232. In particular, gasburner assembly 120 may have a respective heat output at each positionof control knob 112 (and fuel regulating device 236), e.g., an off,high, medium, and low position. In addition, control knob 112 may berotated to a lighting position to supply a suitable amount of gaseousfuel to primary burner 130 for ignition, which may be simultaneouslyachieved using, e.g., a spark electrode (not shown).

As best shown in FIG. 10, supply line 232 is split into a first branch(e.g., a primary fuel conduit 240) and a second branch (e.g., a boostfuel conduit 242) at a junction 244, e.g., via a plumbing tee, wye, orany other suitable splitting device. In general, primary fuel conduit240 extends from junction 244 to an orifice for primary flame ports 134(such as first gas orifice 156), which is positioned for directing aflow of primary fuel 246 into gas burner assembly 120, or moreparticularly into primary burner 130. Similarly, boost fuel conduit 242extends from junction 244 to an orifice for boost flame ports 138 (suchas second gas orifice 164 or holes 182 defined therein), which ispositioned for directing a flow of boost fuel 248 into boost burner 132.Thus, supply line 232 is positioned upstream of primary and boost fuelconduits 240, 242 relative to a flow of gaseous fuel from fuel source152 and primary and boost fuel conduits 240, 242 may separately supplythe gaseous fuel from supply line 232 to primary burner 130 and boostburner 132.

As explained above, boost burner 132 is a forced air or mechanicallyaspirated burner. As illustrated, fuel supply system 230 includes apressurized air source 160 which is generally configured for providingthe flow of combustion air 250 to boost burner 132 for mixing with boostflow of fuel 248. In this regard, for example, fuel supply system 230includes an air supply conduit 252 that provides fluid communicationbetween pressurized air source 160 and boost fuel chamber 140, or morespecifically, outlet 180 of air passage 172. It should be appreciatedthat any suitable type, position, and configuration of pressurized airsource 160 is possible and within the scope of the present subjectmatter. For example, according to an exemplary embodiment, pressurizedair source 160 may be a bellows-style air pump, a fan, such as an axialor centrifugal fan, or any other device suitable for urging a flow ofcombustion air, such as an air compressor or a centralized compressedair system. Pressurized air source 160 may be configured for supplyingthe flow of combustion air 250 at any suitable gage pressure, such as ahalf to one psig.

As described above, fuel supply system 230 includes pneumaticallyactuated gas valve 200, which is a pressure controlled valve operablycoupled with pressurized air source 160 and to boost fuel conduit 242.Pneumatically actuated gas valve 200 is generally configured forregulating the flow of boost fuel 248 passing through boost fuel conduit242, as described in detail above. Specifically, pneumatically actuatedgas valve 200 is configured for stopping the flow of boost fuel 248 whena pressure of the flow of air 250 drops below a predetermined pressureor threshold.

As shown in FIG. 10, a boost button 260 may be operably coupled topressurized air source 160 through controller 220. In this regard, boostbutton 260 may be a momentary push button, a toggle switch, or any othersuitable button or switch that is operably coupled with controller 220for providing an indication to gas burner assembly 120 and pressurizedair source 160 to enter boost mode. Thus, when boost burner button 260is pressed, controller 220 may operate pressurized air source 160 tostart boost mode operation. As an example, boost flame ports 138 may beactivated by pressing a boost burner button 260 on control panel 110. Inresponse to a user actuating boost burner button 260, pressurized airsource 160 may be activated, e.g., with a timer control or withcontroller 220.

Referring still to FIG. 10, gas burner assembly 120 may include a fueltype switch 262 which is operably coupled to controller 220. Fuel typeswitch 262 is generally configured for informing controller 220 whattype of fuel is being used with gas burner assembly 120. For example,gas burner assembly 120 may be configured for operating using anysuitable gaseous fuel such as propane, natural gas, butane, etc.However, the appropriate amount of air supplied to boost burner 132 mayvary depending on the fuel type used. Thus, for example, if a user ormaintenance technician modifies gas burner assembly 120 to operate witha compatible fuel that is different than that for which the burner andpressurized air source 160 are programmed, the fuel type switch 262 maybe used to adjust operation of the pressurized air source 160accordingly. Similar to boost button 260, fuel type switch 262 may be amomentary push button, a toggle switch, or any other suitable button orswitch that is operably coupled with controller 220 for providing anindication as to the type of fuel used.

Now that the construction and configuration of gas burner assembly 120and fuel supply system 230 have been described according to exemplaryembodiments of the present subject matter, exemplary method 300 (FIG.11) and 400 (FIG. 13) for operating a gas burner assembly will bedescribed according to an exemplary embodiment of the present subjectmatter. Methods 300 and 400 can be used to operate gas burner assembly120, or any other suitable heating element or cooktop appliance. In thisregard, for example, controller 220 may be configured for implementingsome or all steps of methods 300 and 400. Further, it should beappreciated that the exemplary methods 300 and 400 are discussed hereinonly to describe exemplary aspects of the present subject matter, and isnot intended to be limiting.

Referring now to FIG. 11, method 300 includes, at step 310, stopping theflow of fuel using a fuel regulating device. Specifically, the stoppingof the flow of fuel may be initiated by controller 220 when the usercommands or the controller determines that the gas burner should beextinguished. According to an exemplary embodiment, the process ofstopping the flow of fuel may include instantaneously changing a voltageor a valve control signal (e.g., a pulse width modulation signal) thatis supplied to fuel regulating device 236 to close the fuel regulatingdevice 236 or otherwise prevent further flow of fuel. Alternatively, theprocess of stopping the flow of fuel may be performed by a usermanipulating a control knob (e.g. control knob 112) or otherwise closinga valve which stops the flow of fuel.

In this regard, when a boost mode of gas burner assembly 120 isinitiated (e.g., as indicated by reference numeral 270 in FIG. 12), thepressurized air source or air pump 160 quickly ramps up to provide aflow of air to mix with the simultaneously provided flow of fuel 248through fuel regulating device 236. During the boost mode, air pump 160may provide a constant or substantially constant flow of air into boostfuel chamber 140 (e.g., as indicated by steady state operation segment272 of the air pump voltage curve in FIG. 12). In this regard, when fuelregulating device 236 is open and providing a constant stream of fuelinto primary chamber 126 (e.g., primary fuel 246) and into boost fuelchamber 140 (e.g., boost fuel 248), air pump 160 may be simultaneouslyproviding a constant flow rate of air into boost fuel chamber 140 toachieve the desired fuel/air mixture for proper combustion.

Notably, when the gas burner 120 is extinguished or terminated (e.g., asindicated at reference numeral 274 in FIG. 12), the flow of fuelprovided through fuel regulating device 236 is instantaneously stopped(e.g., as specified in step 310). In this manner, both the primary flowof fuel 146 and the boost flow of fuel 248 are stopped. As explainedbriefly above, if the flow of air provided to boost chamber is alsoinstantaneously stopped, an extinction popping noise may be generated asthe fuel mixture within boost burner 132 becomes excessively lean.Aspects of method 300 are directed to preventing this undesirablepopping or flame extinguishing noise when a gas burner is turned off.

Specifically, method 300 further includes at step 320, ramping down theoperation of the air pump to slowly stop the flow of air provided to theboost burner. Specifically, according to one embodiment, the rampingdown of the air pump may be indicated by line 276 in FIG. 12, where thevoltage applied to the air pump 160 is slowly decreased over apredetermined time period (indicated by reference numeral 278) such thatthe corresponding flow of air generated by air pump 160 also decreasesslowly over that time. Notably, by slowly tapering off the flow of airto boost fuel chamber 140, a lean fuel/air mixture and the correspondingextinction pop may be avoided.

In general, “ramping down” or slowly decreasing the flow rate from theair pump 160 is generally intended to refer to stopping the operation ofair pump 160 or the flow of air 250 over a longer time period than wouldresult from instantly stopping the air pump 160 or cutting the voltageor control signal driving the air pump 160. This ramping down proceduremay be achieved in various manners, examples of which will be describedherein. However, the examples provided are not intended to limit thescope of the subject matter in any manner.

As illustrated in FIG. 12, ramping down the operation of the air pumpmay include decreasing the voltage to the air pump at a constant rate.In this manner, as shown by line 276, the slope of the voltage decreaseover time may be constant. However, it should be appreciated thataccording to alternative embodiments, the output of air pump 160 may beramped down according to a time varying rate. In other words, the slopeof line 276 need not be constant, but may vary with time, may include aseries of step downs in voltage, or may vary according to any othersuitable schedule or profile that is determined empirically ortheoretically to improve the combustion during burner termination.

For example, ramping down the operation of the air pump may includereducing the output of the air pump from steady state (e.g. as indicatedby 272) to zero (e.g., as indicated by 280) over the predetermined timeperiod 278. In this regard, for example, the predetermined time periodcould be between about 0.1 and 5 seconds, between about 0.5 and 3seconds, or about 1 second. However, it should be appreciated that thepredetermined time period may vary depending on burner type,configuration, size, fuel type, combustion characteristics, etc.Further, it should be appreciated that as used herein, terms ofapproximation, such as “approximately,” “substantially,” or “about,”refer to being within a ten percent margin of error.

In addition, although FIG. 12 illustrates a pump voltage for regulatingthe operation of air pump 160, it should be appreciated that othercontrol signals and methods for regulating the operation of air pump 160may be used while remaining within the scope of the present subjectmatter. In this regard, for example, controller 220 or air pump 160 mayinclude a dedicated power supply and controller 220 may regulate airpump 160 operation with an output control signal. Output control signalmay be any suitable digital control signal, such as a pulse widthmodulated signal having a duty cycle that is roughly proportional to thepower level or output of air pump 160. In this regard, for example, afifty percent duty cycle may drive air pump 160 at fifty percent of itsrated output, an eighty percent duty cycle may drive air pump 160 ateighty percent of its rated output, etc. It should be appreciated thatother means for controlling the power level and output of air pump 160are possible and within the scope of the present subject matter.

According to still other embodiments, controller 220 and may adjust theramping down process based on the type of fuel used with gas burnerassembly 120. In this regard, the appropriate amount of air supplied toboost burner 132 may vary depending on the fuel type used (e.g. whichmay be set by fuel type switch 262). According to such an embodiment,method 300 may further include obtaining the fuel type of the flow offuel and selecting an output control signal for slowing down the airpump that corresponds to the fuel type used. In this regard, controller220 may include various ramp down profiles that correspond to respectivetypes of fuels. The controller may then adjust the output control signal(e.g., a pump voltage or pulse width modulated signal) according to thetime-varying or constant ramp down profile.

Notably, method 300 describes a control method during which the entireflow of fuel to the gas burner 120 is shutoff, e.g., when a usermanually closes fuel regulating device 236 to stop the flow of fuel toboth primary burner 130 and boost burner 132. In such an embodiment, theflow of air is dropped over time to keep the flow velocity high exitingthe boost flame ports 138 to keep the flame front from retreating intoboost fuel chamber 140. In this regard, the flow of air is provided intoboost fuel chamber 140 after the fuel regulating device 236 has beenclosed in order to purge the boost burner 132 with air flow.

Referring now to FIG. 13, an exemplary method 400 of operating gasburner 120 will be described according to an exemplary embodiment.Specifically, method 400 may be used to mitigate extinction pop whenboost burner 132 is deactivated but primary burner 130 is stilloperating (e.g., fuel is still being provided through fuel regulatingdevice 236. It should be appreciated that the deactivation of the boostmode may be achieved in any suitable manner, e.g., by pressing boostbutton 260, using control panel 110, etc.

Method 400 includes, at step 410, ramping down the operation of an airpump to slowly stop a flow of air until a pressure of the flow of airdrops below the predetermined threshold to close a pneumaticallycontrolled valve and stop a flow of fuel to a boost burner.Specifically, continuing the example from above, when boost mode isactivated, fuel regulating device 236 may provide the flow of fuel 234which is split into the primary flow of fuel 246 and the boost flow offuel 248. If a user wishes to exit boost mode while still operating theprimary burner 130, the boost button 260 may be pressed, which causesair pump 160 to throttle down slowly (similar to the manner describedwith respect to FIG. 11) until the pneumatically controlled valve closesand stops the boost flow of fuel 248.

Notably, when this occurs, fuel regulating valve 236 is still open andprimary burner 130 may still operate. However, the flow of fuel intoboost fuel chamber 140 stops, potentially resulting in a lean fuelmixture in a manner similar to that described above. To prevent this,method 400 further includes, at step 420, continuing to ramp down theoperation of the air pump to slowly stop the flow of air to the boostburner. Notably, by slowly ramping down the flow of air after the flowof boost fuel has stopped, extinction pop is reduced or eliminatedaltogether, e.g., for reasons similar to that described above.

FIGS. 11 and 13 depicts exemplary control methods having steps performedin a particular order for purposes of illustration and discussion. Thoseof ordinary skill in the art, using the disclosures provided herein,will understand that the steps of any of the methods discussed hereincan be adapted, rearranged, expanded, omitted, or modified in variousways without deviating from the scope of the present disclosure.Moreover, although aspects of the methods are explained using gas burnerassembly 120 and fuel supply system 230 as an example, it should beappreciated that these methods may be applied to the operation of anysuitable gas burner assembly or cooktop appliance.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method of operating a gas burner assembly, thegas burner assembly comprising a boost burner, a fuel regulating devicefor providing a flow of fuel to the boost burner, and an air pump forproviding a flow of air to the boost burner, the method comprising:stopping the flow of fuel using the fuel regulating device; and rampingdown the operation of the air pump to slowly stop the flow of air. 2.The method of claim 1, wherein stopping the flow of fuel using the fuelregulating device comprises: instantaneously changing a voltage or avalve control signal supplied to the fuel regulating device to close thefuel regulating device.
 3. The method of claim 1, wherein stopping theflow of fuel using the fuel regulating device comprises: manipulating acontrol knob to close the fuel regulating device.
 4. The method of claim1, wherein ramping down the operation of the air pump comprises:decreasing a voltage to the air pump at a constant rate.
 5. The methodof claim 1, wherein ramping down the operation of the air pumpcomprises: decreasing an output of the air pump according to atime-varying rate.
 6. The method of claim 1, wherein ramping down theoperation of the air pump comprises: decreasing an output of the airpump from a steady state output to zero over a predetermined timeperiod.
 7. The method of claim 6, wherein the predetermined time periodis between about 0.1 and 5 seconds.
 8. The method of claim 6, whereinthe predetermined time period is between about 0.5 and 3 seconds.
 9. Themethod of claim 1, wherein ramping down the operation of the air pumpcomprises: obtaining a fuel type of the flow of fuel; and selecting anoutput control signal for slowing down the air pump that corresponds tothe fuel type.
 10. The method of claim 9, wherein the output controlsignal comprises a time-varying voltage signal.
 11. The method of claim9, wherein the output control signal comprises a time-varying frequencycontrol signal.
 12. A method of operating a gas burner assembly, the gasburner assembly comprising a boost burner, a fuel regulating device forproviding a flow of fuel to the boost burner, an air pump for providinga flow of air to the boost burner, and a pneumatically controlled valvefor stopping the flow of fuel when a pressure of the flow of air dropsbelow a predetermined threshold pressure, the method comprising: rampingdown the operation of the air pump to slowly stop the flow of air untila pressure of the flow of air drops below the predetermined threshold toclose the pneumatically controlled valve and stop the flow of fuel; andcontinuing to ramp down the operation of the air pump until the flow ofair stops.
 13. The method of claim 12, wherein ramping down theoperation of the air pump comprises: decreasing a voltage to the airpump at a constant rate.
 14. The method of claim 12, wherein rampingdown the operation of the air pump comprises: decreasing an output ofthe air pump according to a time-varying rate.
 15. The method of claim12, wherein ramping down the operation of the air pump comprises:decreasing an output of the air pump from a steady state output to zeroover a predetermined time period.
 16. A gas burner assembly for acooktop appliance, the gas burner assembly comprising: a boost burnercomprising a plurality of boost flame ports in fluid communication witha boost fuel chamber; a fuel regulating device fluidly coupled to theboost fuel chamber for providing a flow of fuel to the boost fuelchamber; an air pump for selectively urging a flow of air into the boostfuel chamber; and a controller operably coupled to the fuel regulatingdevice and the air pump, the controller being configured for: stoppingthe flow of fuel using the fuel regulating device; and ramping down theoperation of the air pump to slowly stop the flow of air.
 17. The gasburner assembly of claim 16, wherein stopping the flow of fuel using thefuel regulating device comprises: instantaneously changing a voltage ora valve control signal supplied to the fuel regulating device to closethe fuel regulating device.
 18. The gas burner assembly of claim 16,wherein ramping down the operation of the air pump comprises: decreasinga voltage to the air pump at a constant rate or a time-varying rate. 19.The gas burner assembly of claim 16, wherein ramping down the operationof the air pump comprises: decreasing an output the air pump from asteady state output to zero over a predetermined time period.
 20. Thegas burner assembly of claim 16, further comprising: a boost valve forregulating the flow of fuel to the boost fuel chamber, wherein the boostvalve is a pneumatically controlled valve configured for closing whenthe air pump is stopped.